Medical Neuroscience explores the functional organization and neurophysiology of the human central nervous system, while providing a neurobiological framework for understanding human behavior. In this course, you will discover the organization of the neural systems in the brain and spinal cord that mediate sensation, motivate bodily action, and integrate sensorimotor signals with memory, emotion and related faculties of cognition. The overall goal of this course is to provide the foundation for understanding the impairments of sensation, action and cognition that accompany injury, disease or dysfunction in the central nervous system. The course will build upon knowledge acquired through prior studies of cell and molecular biology, general physiology and human anatomy, as we focus primarily on the central nervous system.
This online course is designed to include all of the core concepts in neurophysiology and clinical neuroanatomy that would be presented in most first-year neuroscience courses in schools of medicine. However, there are some topics (e.g., biological psychiatry) and several learning experiences (e.g., hands-on brain dissection) that we provide in the corresponding course offered in the Duke University School of Medicine on campus that we are not attempting to reproduce in Medical Neuroscience online. Nevertheless, our aim is to faithfully present in scope and rigor a medical school caliber course experience.
This course comprises six units of content organized into 12 weeks, with an additional week for a comprehensive final exam:
- Unit 1 Neuroanatomy (weeks 1-2). This unit covers the surface anatomy of the human brain, its internal structure, and the overall organization of sensory and motor systems in the brainstem and spinal cord.
- Unit 2 Neural signaling (weeks 3-4). This unit addresses the fundamental mechanisms of neuronal excitability, signal generation and propagation, synaptic transmission, post synaptic mechanisms of signal integration, and neural plasticity.
- Unit 3 Sensory systems (weeks 5-7). Here, you will learn the overall organization and function of the sensory systems that contribute to our sense of self relative to the world around us: somatic sensory systems, proprioception, vision, audition, and balance senses.
- Unit 4 Motor systems (weeks 8-9). In this unit, we will examine the organization and function of the brain and spinal mechanisms that govern bodily movement.
- Unit 5 Brain Development (week 10). Next, we turn our attention to the neurobiological mechanisms for building the nervous system in embryonic development and in early postnatal life; we will also consider how the brain changes across the lifespan.
- Unit 6 Cognition (weeks 11-12). The course concludes with a survey of the association systems of the cerebral hemispheres, with an emphasis on cortical networks that integrate perception, memory and emotion in organizing behavior and planning for the future; we will also consider brain systems for maintaining homeostasis and regulating brain state.

Conoce a los instructores

Leonard E. White, Ph.D.

Associate ProfessorDepartment of Neurology, Department of Neurobiology, Duke University School of Medicine; Department of Psychology & Neuroscience, Trinity College of Arts & Sciences; Director of Education, Duke Institute for Brain Sciences; Duke University

Now, with some overview of the white matter and gray matter of the spinal cord,

I want us to turn to a very important consideration.

And that is understanding what we find at each level of the spinal cord.

And here's, I think, a very helpful figure.

What it does is it shows representative cross-sections that are taken from

different levels of the spinal cord. And I want you to notice a few features

that we find here. Essentially, what we find is that in the

region of the cervical spinal cord, and also, in the lumbosacral enlargement

region, we see an expansion of the amount of gray matter that's present in the

ventral horn. I think that should make good sense to

you. This gray matter is providing motor output

to the arms, in the case of the cervical cord, and to the legs in the case of the

lumbosacral enlargement. So, more neurons, more local circuits

means more grey matter volume that's governing what we do with our appendages

on our arms and our legs. In the thoracic spinal cord, notice that

the amount of grey matter in the ventral horn is reduced, compared to what we find

in the cervical and in the lumbar and sacral levels.

Okay, so, look at how much gray matter we have in the ventral horn, that will help

you identify the section. I also want you to notice the amount of

white matter that we have here in the spinal cord.

Now, for the amount of white matter in the cord.

I think it should make a certain amount of sense that it would decrease as we move

from superior to inferior. And it's decreasing for 2 reasons.

One reason is that the axons that are coming down from the brainstem and

cerebral cortex and the lateral and anterior column of white matter are simply

terminating along the way. So, if we looked at the upper levels of

the spinal cord we would expect to find more axons than if we were to look at the

lower levels of the spinal cord. Now, for a similar reason, our ascending

pathways that are sending signals, let's say about pain and temperature or

mechanosensation, up through the spinal cord are collecting at various levels.

And as a consequence, in the superior segments of the spinal cord we have more

axons conveying ascending sensory signals than we have at more inferior levels.

Now, if we then look at the cross sections of the spinal cord, I think it should be

obvious to you that we have a whole lot more white matter here in the cervical

cord compared to the very bottom of the spinal cord in the sacral region.

So, look for the amount of white matter that we find.

And we see that there is more white matter at the upper levels than in the lower

levels. Now, one key difference that I want you to

look for is the lateral margins of the grey matter of the spinal cord.

You'll note that in the thoracic cord there is a lateral protrusion from the

gray matter right near the junction of the ventral horn and the dorsal horn.

This is a feature that we call the lateral horn.

And this is a distinctive feature of the thoracic spinal cord.

And as we'll see, what's in that lateral horn are preganglionic sympathetic

neurons, that are providing outflow from the nervous system to the viscera.

We see a similar group of cells in the sacral cord, but they tend not to form a

pointy protrusion into the white matter. And at that level we don't call that a

lateral horn, but we do recognize another collection of preganglionic visceral motor

neurons, only in the sacral cord they're parasympathetic, whereas in the thoracic

cord they're sympathetic. All right.

Another key distinction that we need to make when we look at the spinal cord is in

the region of the dorsal column. So, remember the dorsal column is what we

find out here with dorsal being shown to the top of the image and ventral or

anterior to the bottom. What I want you to notice is that in the

dorsal column, there is more white matter in the cervical region, compared to the

lumbosacral enlargement for reasons that I just illustrated for you.

But I also want you to note that in the cervical cord, there is a distinction

between a lateral component of this white matter, and a medial component.

And as we talk about our pathways for mechanosensation, what you'll discover is

that the medial component is what we find at lower levels of the spinal chord.

But as we get into the region of the cervical enlargement, we begin to add

white matter from the sensory inputs that are attached to that cervical enlargement,

serving the upper extremities. While that wet matter begins to add up in

the lateral aspect of this dorsal column and the upper thoracic cord.

And then, we really see it adding up as we move through the cervical enlargement.

So, look for those divisions of the dorsal column when we look at cross sections

through the spinal cord. And we'll, we'll give these divisions

names. I don't need to tell them to you now but,

but just note that in the cervical cord the dorsal column is subdivided, whereas

in the lumbar and sacral levels, there's no such subdivision of the dorsal column.

Okay, now, I think we're ready to name some of these details.

And give you a chart that will allow you to explore on your own, cross sections

through the human spinal cord. So, this is a chart that lays out for you

some important internal features, in terms of grey matter and white matter.

And for white matter, I'm giving you the names of some of these important tracks or

pathways, that we will talk about in detail when we talk about mechanosensation

and our systems for pain and temperature. Well, let me orient you to this chart.